This invention relates to marine drives and more particularly to an outboard drive for a marine engine which is inside the boat.
So called inboard-outboard drives have been in use for some time. An example is shown in U.S. Pat. No. 1,798,596 Fahrney which shows a "through-the-transom" drive. These drives propel boats having large engines, typical of inboard engines. The drives also have many of the advantages of outboard motors. For example, the drives can be rotatably lifted so that the propeller shaft can be lifted when the boat is in shallow water. Or, the entire unit can be lifted for inspection and maintenance of the propeller and its shaft.
In addition to tilting upward, the outboard drives are rotatable about a generally vertical axis to steer the boat. One common arrangement provides a universal joint about which the drive can be both tilted and steered. Such an arrangement is shown in U.S. Pat. No. 3,088,296.
In order to conserve space on the boat, it is desirable to have the engine mounted as near to the transom as possible. This has not been possible with prior art drives because they required space between the transom and the engine for steering and gear shift linkages to rotate as the motor is tilted about its pivot point. See for example, U.S. Pat. No. 2,977,923 wherein the point 24 is the pivot point and it is outside of the boat. A relatively large space between the transom and the engine must be provided to accommodate shift and steering linkages which must rotate as the drive is pivoted about this point.
U.S. Pat. No. 3,382,838 Bergstedt shows a marine drive in which the pivot point is inside the boat. However, with this type of drive it is not possible to put the transmission at the point where the drive shaft joins the generally vertical shaft of the drive. As will be apparent subsequently, this is desirable because the transmission can be inserted at this point with the addition of a minimum number of gears. Also, it is desirable to accommodate the steering linkage within the drive casing whereas in the Bergstedt patent the steering linkage is external to the drive and a separate hole through the transom must be provided to accommodate it.